Warren is a city in Macomb County in the U.S. state of Michigan. An inner-ring suburb of Detroit, Warren borders Detroit to the north, roughly 13 miles (20.9 km) north of downtown Detroit. As of the 2020 census, the city had a population of 139,387, making Warren the largest community in Macomb County, the third-largest city in Michigan, and Detroit's largest suburb. The city is home to a wide variety of businesses, including General Motors Technical Center, the United States Army Detroit Arsenal, home of the United States Army TACOM Life Cycle Management Command and the Tank Automotive Research, Development and Engineering Center (TARDEC), and the headquarters of Asset Acceptance.